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When skiing the bindings holding your boot in place withstand a lot of force. Ski bindings have to perform a complicated balancing act – they work as a performance device and a safety device at the same time. How can they do both things at the same time?
Ski bindings act as the interface between the boot and the ski. The boot needs to be held firmly in the binding to transfer all the skier’s movements, down through the boots to the skis. Ski bindings need to be tight enough so there is little play between the boot & the binding. However, if you fall the bindings need to have enough play so that the ski comes away from the boot lowering the likelihood of injury.
When Were Bindings First Used?
Ski bindings were first developed during the 1930s but were very basic in design. They consisted of a metal toecap, which the leather boot would be pushed into, while at the back a steel cable would wrap around the heel to secure the boot to the ski.
Complications arose because it was difficult to secure the pliable soft leather boot adequately. Also, with no active release mechanism injuries were common.
During downhill events, it wasn’t unusual for more than 25% of racers being taken to hospital. There were numerous attempts to create safer and more effective bindings but there were still many injuries from falls.
In 1937, Hjalmar Hvam, a Norwegian who had emigrated to the US invented a basic release mechanism that forms the design of current-day bindings.
Hvam imagined a simple pivoting clip, which notched into the boot’s sole. An internal mechanism held the pivot centered if the boot toe pressed upward against the clip. However, if that pressure was removed, as in a severe forward fall, the clip was freed to swing sideways allowing the ski to separate.
Many small improvements and new designs came onto the market, but it wasn’t until the early 1960s, when a German rocket scientist, Robert Lusser, revolutionized bindings with his own design. He used a flexible toecap at the front and a heel release system based on a heel cup. The full history of binding development is complicated.
What Are The Different Working Parts Of A Binding?
When attaching bindings to a new ski a riser plate is sometimes attached between the binding and the ski. This serves two functions, firstly it raises the height of the binding, which gives the skier extra power on corners, and secondly, the riser plate can be filled with shock-absorbing material to minimize vibration coming up through the ski.
1. Toe Section – Nowadays the standardized binding has a toe section, which the lip on the front of the ski boot slots into. The boot is held in place by two tensioners on either side, which are sprung independently. The front of the binding lets the boot release sideways if there is a large twisting force.
2. Heel Section – At the heel section, the rear boot lip is pushed down into the heel mechanism until it clicks when the binding is gripping the boot correctly. The back of the binding will release the ski boot upwards if there is a large forward force on the boot.
3. Brake System – Ski bindings incorporate a ski brake system. The brakes consist of two arms towards the back of the binding, which swings down below the bottom of the ski.
The brake is designed to only work when the ski is detached from the boot. Without such a brake, after a fall, it wasn’t unusual for skis to slide considerable distances and it stops the ski from interacting as much with the falling skier.
The ski brakes also make it a lot easier to put skis on when standing on steep runs. When you push your boot into the binding, the boot presses down on the brake pedal, which lifts the brakes out of the snow, and tucks them in under the ski boot, so that they are out of the way while skiing.
4. Anti-Friction Device(AFD) – Ensures sideways forces from the ski boot are transmitted into the toe section and not into the base of the binding. The AFD also lets the ski boot slide sideways as easily as possible when the toe section releases the boot.
There are several designs, usually situated under the front of the ski boot. One design consists of a spring-loaded plate, while others are a simple plate with a low friction metal surface.
Why Does The Ski Shop Assistant Tighten The Binding With A Screwdriver?
So, we have all seen the guys and girls in the ski shop looking at their notes, doing a quick calculation, and then adjusting your ski bindings at the front and back with a screwdriver.
What Does That Do?
They are adjusting the tension of the binding fittings so that there is just enough tension to make sure the ski does not come off inadvertently, but at the same time making sure your binding has enough play to make the ski separate if you fall.
The amount of force needed to make your ski separate from the boot is dependent on a variety of factors, but three critical ones are your skiing ability, weight, and your height. These go into what’s called the DIN calculation.
If you are a heavier person in a fall your body will exert a higher twisting force to separate your skis than a lighter person. Similarly, a taller person will exert a higher twisting force than someone who is short.
Is There A Standard Way Of Adjusting Bindings?
The settings for the tension adjustment have been internationally standardized in Germany under the abbreviation DIN. This stands for Deutsches Institut für Normung (German Institute for Standardization) and is the industry standard scale for release force settings for ski bindings.
On the front and back of each binding, there is a small window with a scale inside. Adjusting the tension of the binding with a screwdriver moves the scale up and down so the required tension can be set. The settings for the front and the back of the binding are adjusted separately, and sometimes can be set to different values if required, although normally they are set to the same value.
Are All Ski Bindings The Same?
Nowadays all ski boots are made to a standard so the lip on the toe and heel are the same dimensions. This means any ski boot will fit any ski. The only exception is for adults and children.
Similarly, bindings and ski boots are designed so that ski boots will only fit in bindings in one direction, making it impossible to put the boot in backward. To put the boot in the binding the lip on the front of the boot has to slide into the toe cup on the front of the binding, and then the back lip is lined up with the heel cup on the back of the binding and pushed down until the mechanism is activated. The heel cup then rotates to clamp down on the back lip of the ski boot and the heel lever clicks upwards.